Combined sight tube and magnetic compass



1961 E. F. MIXNER 2,970,510

COMBINED SIGHT TUBE AND MAGNETIC COMPASS Filed Feb. 20, 1959 IN V EN TOR.

sow/220 FT M/X/VEQ 44 yl %mw flman -EM Uniii States Patent i' COMBINED SIGHT TUBE AND MAGNETIC COMPASS Edward F. Mixner, Goshen, NJ.

Filed Feb. 20, 1959, Ser. No. 794,654

Claims.- (Cl. 88--2.3)

This invention relates to an optical instrument and comprises a continuation-in-part of my co-pending application, filed February 11, 1958, Serial No. 714,536, now abandoned, and entitled Combined Telescope and Magnetic Compass. More specifically, the instant invention pertains to optical devices for obtaining bearing readings and comprises, essentially, a combined telescope and magnetic compass primarily designed and adapted for use as a navigation instrument. One of the principal uses of the present instrument is to take compass readings on one or more stationary objects, the readings being used in conjunction with navigation charts in order to establish a definite location or position.

One of the primary objects of this invention is to provide a combined telescope and magnetic compass wherein a bearing reading may be obtained simultaneously with the sighting of the telescope on a predetermined target.

' This invention contemplates, as a still further object thereof the provision of a telescope device of the type described, the device being non-complex in construction and assembly, inexpensive to manufacture and maintain and durable in use.

Other and further objects and advantages of the instant invention will become more evident from a consideration of the following specification when read in conjunction with the annexed drawing, in which:

Figure 1 is a perspective view of an optical device constructed in accordance with this invention;

Figure 2 is an enlarged detail medial cross-sectional view taken substantially on the vertical plane of line 22 of Figure 1, looking in the direction of the arrows;

Figure 3 is an enlarged detail cross-sectional view taken substantially on the line 3-3 of Figure 2, looking in the direction of the arrows; and, t

Figure 4 is an enlarged fragmentary top plan view of the compass disc or card.

Referring now more specifically to the drawings, reference numeral designates an optical instrument or device, in general, constructed in accordance with the teachings of this invention. The device 10 is seen to comprise a substantially hollow cylindrical brass casing 12 having a cylindrical side wall 14 across the base end of which extends a closure or bottom wall 16. At the .juncture of the side wall 14 with the bottom wall 16 is disposed an annular sealing gasket 18 against which rests in sealing or liquid-tight engagement the lower end of a cylindrical side wall 20 of an inverted bowl 22 formed of Plexiglas and having a closure or top wall 24. As is The top wall 24 has integrally formed therewith a pair.

of elongated concave-convex reservoirs 26, 28 having their respective concave sides opening into the bowl 22. As is clearly seen in Figures 1 and 3, the reservoirs 26,

28 are parallel and are laterally spaced from each other on opposite sides of a diameter of the bowl 22. To serve a function to be described, the top wall 24 is formed 2,970,510 Patented Feb. 7, 1961 ice versely extending countersunk opening 38 which is co,-

axially aligned with an aperture 40 located substantially at the center point of the bottom wall 16.

A screw 42 extends through the opening 38 and is threaded into the aperture 40 for extension into the bowl 22 with the head 44 thereof received within the opening 38. On the inner end of the screw 42 is threaded a brass bearing staff 46 having a pointed end 48.

An inverted substantially lJ-shaped bracket is denoted at 54) and includes a normally horizontal bight member 52 having depending flanges 54, 56, respectively, at its opposed ends. The flanges 54, 56 are suitably apertured to receive therethrough a pair of laterally spaced, elongated and substantially parallel bar magnets 58, 61

A compass card or disc 62 formed of a non-magnetic material, such as a transparent plastic, is provided adjacent its circumferential marginal edge with inverted opaque compass indicia 64 (see Figure 4). The disc 62 and bight member 52 are formed with centrally disposed aligned apertures to serve a function to be described, and these two elements are secured together by conventional means 65. The last mentioned apertures receive therethrough an externally threaded jewel cap 66 having a radial flange 68 at one end thereof, the latter being adapted to engage against and support the bight member 52 and its superimposed disc 62. An internally threaded clamp cap 70 having a side wall 72 is mounted on the jewel cap 66 with the lower end of the side wall 72 engaging the upper side of the disc 62 whereby the flange 68 and side wall 72 clamp the disc 62 and bight member 52 therebetween. The jewel cap 66 is formed with the usual conical recess 74 to receive the tip 48 of the bearing staff 46 therein.

The device 19 includes an elongated open ended brass telescope tube 76 comprising a hollow cylindrical side wall 78 having a throat member 80 in open communication therewith adjacent one of its respective ends. As is clearly seen in Figure 3 2, the lower or outer end of the throat 86 terminates in a hollow cylindrical collar 82 which telescopes in the recess 38 and engages the side wall 32 thereof. The tube 76 extends diametrically across the top wall 24 between the reservoirs 26, 28and is secured against movement relative to the bowl 22 by means of a pair of inverted U-shaped clamping brackets 84 located, respectively, adjacent each -end of the tube 76. As is seen in the drawing, the bight portions 86 of the brackets 84 engage over the upper side of the tube 76 and the depending arms 88, 90 project through the extended ends of the clamp plate 36 for connection with cap nuts 92.

figuration, and secured within the lower half of the tube as by means of an adhesive 100. i

A combined transparent plate and mirror holding tube -is designated at 102, the tube ltl2being telescoped within the other end ofthe tube 76 and secured thereto by. conventional means. As is seen in Figure 2, a second transparent plate 104 is secured to the outer end of the tube 102 by an adhesive 106., The inner end of the tube 102 is cut away on an acute angle of substantially 45 degrees with respect to its longitudinal axis, and to the lower end of the cutout is connected a chord shaped mirror 108 having its chord line 110 flush with the upper end of the lens 98. The mirror is provided with an unsilvered rectangular transparent area 112 which is substantially perpendicular to the chord line 110 in bisecting relation relative thereto, the area 112 serving a function to be described.

The tube 102 is formed with a pair of diametrically opposed openings 114, 116 in which are anchored the opposed ends of a wire hairline 118 normally positioned in a vertical plane. As is seen in Figure 2 the hairline 118 is disposed in the tube 102 intermediate the mirror 108 and the lens 104. 7

As is seen in Figure 3 of the drawing, the bowl 22 is filled with any suitable fluid 120 which normally serves as a lubricant for the jewel cap 66 but in addition thereto the fluid extends to a heighth above the disc 62 and acts as a damping means therefor.

In using this optic device, the user holds the sighting end of the tube 76 against his eye with the hairline 118 positioned substantially vertical. A sight is then taken on a target (not shown) and the instrument is held in this given position until the disc 62 reaches the end of its rotation and the hairline is aligned with the transparent area 112 and is visible therethrough. The indicia on the compass 62 is reflected on the mirror 108 and is read through the lens 98 and plate 96. Thus the operator is immediately provided with means for determining the angular deviation of the established sight line relative to magnetic North.

The device may be readily used under conditions of low illumination, for example, in night operations by merely holding a flashlight or other light source below the transparent top wall 24 of the bowl 22 for diffusion through the liquid 120 in order to effect illumination of the opaque indicia 64.

The reservoirs 26, 28 are not completely filled in order to provide suflicient room for expansion of the liquid 120 when the device is being operated under extremely hot conditions.

Having described and illustrated one embodiment of this invention in detail, it will be understood that the same is ofiered merely by way of example, and that this invention is to be limited only by the scope of the appended claims.

What is claimed is: 1

1. An optical device comprising a substantially hollow cylindrical housing having a transparent wall extending across one end thereof, a disc having magnet means thereon and being supported for rotation within said housing, said disc having compass indicia thereon adjacent its circumferential marginal edge, said disc being supported adjacent to but spaced from said wall, a telescope sighting tube formed of opaque non-magnetic material fixedly secured to said wall and having a pair of sighting systems therein, a sight wire hairline extending vertically in said tube in one of said sighting systems, said tube having a throat portion projecting laterally therefrom and towards said transparent wall for engagement therewith, said throat opening above the path of movement of said indicia, and a mirror in said sighting system, said mirror being disposed within said tube and inclined at an acute angle with respect to the longitudinal axis thereof and being disposed over said indicia to reflect the same through said second sighting system, said mirror having a transparent space thereon vertically aligned with said wire hairline,

said hairline being visible across said reflected indicia to provide a compass reading, and means releasably securing said tube on said housing.

2. A sighting compass comprising a housing, said housing including a transparent top wall and a base, the top wall having a recess formed therein; an elongated clamp plate, said clamp plate including opposite, apertured end portions which project outwardly on opposing sides of the base of the housing; compass means, including directional indicia, operably disposed in the housing in such location that the indicia are adapted to be selectively disposed subjacent said recess; an elongated sight tube of at least the length of said clamp plate, said sight tube including a depending, open throat adapted to be positioned in said recess of said housing; reflective means in said sight tube mounted in such location that the indicia subjacent said recess are reflected thereby through one end of said tube; vertically positioned sight wire means in the sight tube; and bracket means including a pair of generally U-shaped brackets, each having a' bight portion and a pair of arms, the bight portions being arranged in clamping engagement with the opposite ends of the tube, and the arms being disposed through the apertures in said clamp plate, and fastening means secured to said arms.

3. A sighting compass comprising a housing, said housing including a transparent top wall and a base, the top wall having a circular recess formed therein and having a pair of spaced apart, outwardly projecting reservoir elements located on opposite sides of the recess; an elongated clamp plate, said clamp plate including opposite, apertured end portions which project outwardly on opposing sides of the base of the housing; compass means, including directional indicia, operably disposed in the housing in such location that the indicia are adapted to be selectively disposed subjacent said recess; an elongated sight tube of at least the length of said clamp plate, said, sight tube including a depending, open throat adapted to be positioned in said recess of said housing with said tube located between said reservoir elements; reflective means in said sight tube mounted in such locations that the indicia disposed subjacent the recess are reflected thereby through said tube; vertically positioned sight wire means in the sight tube; and bracket means including a pair of generally U-shaped brackets, each including a bight portion and a pair of arms, the bight I portions being arranged in clamping engagement with the opposite ends of the tube, and the arms being disposed through said apertures in said clamp plates, and fastening means secured to said arms.

4. A sighting compass comprising a housing; compass means operable disposed in said housing, said compass means including directional indicating indicia; a sight tube secured to the housing over the compass means; said sight tube including open communication means projecting into the housing, and the sight tube having a viewing end and an object end; a mirror in said tube arranged to partially overlie said open communication means, said mirror being disposed at a selected angle with respect to said indicia on said compass so as to reflect that indicia which indicates the direction of alignment of the tube toward said viewing end of said tube, said mirror having an elongated, vertically extending clear area at the center thereof; a sight wire vertically bisecting said tube and arranged between the mirror and the object end of the tube, said sight wire, when aligned with the clear area of the mirror, serving to definitely indicate the direction of longitudinal alignment of the tube.

5. A sighting compass as defined in claim 4, and a magnifying half-lens positioned in the tube between said mirror and said viewing end, the magnification of the lens being such that both the sight wire and the indicia are clearly viewable from the viewing end of the tube.

References Cited in the file of this patent FOREIGN PATENTS 3,122 Great Britain of 1915 16,301 Great Britain of 1915 

